High photodetection performance on vertically oriented topological insulator Sb2Te3/Silicon heterostructure

The coexistence of bulk electronic band gap and gapless surface states of topological insulators (TIs) opens up many new opportunities in optoelectronic devices. Here we demonstrate the synthesis and photodetection response of vertical Sb2Te3 nanoplate film grown on n-type Si substrates. The small bulk bandgap of Sb2Te3 and surface states conduction lead to effective light absorption and photocarrier transport. The device exhibits a significant photoresponse over a broad spectral range between 350 and 1400 ​nm. The switching speed and on/off ratio Iph/Id are estimated to be 3 ​ms and 5900, respectively, which are much better than those of other TI-based photodetectors. Given the simple device preparation and compatibility with silicon technology, the unconventional structure Sb2Te3/Si heterostructure holds great promise for high-performance optoelectronic applications.